Stents have gained acceptance in the medical community as a device capable of supporting body lumens, such as blood vessels, that may have become weakened or susceptible to closure. Typically, a stent is inserted into a vessel of a patient after an angioplasty procedure has been performed to open a stenosed region of a vessel. After the catheter used to perform angioplasty has been removed from the patient, a tubular stent maintained in a small diameter delivery configuration at the distal end of a delivery catheter can be navigated through the vessels to the site of the stenosed area. Once positioned at the site of the stenosis, the stent is released from the delivery catheter and expanded radially to contact the inside surface of the vessel. The expanded stent provides a scaffold-like support structure to maintain the patency of the region of the vessel engaged by the stent, thereby promoting blood flow.
Currently, a variety of stent designs exist having differing mechanisms of expansion, materials, surface configurations and methods of manufacture. Some expandable stents are expanded from a compact delivery diameter to a larger, implanted diameter by the inflation of a balloon located within the stent. Alternatively, stents may be expanded by internal forces in the stent material such as resilient forces created by elastic deformation of the stent to its smaller diameter or by the forces created within a shape memory alloy material, such as nitinol, upon temperature elevation. Various biocompatible materials can be used for a stent such as stainless steel, nitinol and a wide range of polymers, including bioabsorbable materials. Methods of making a stent include coiling or bending wire into a tubular shape, perforating a flat sheet of material and rolling it into a tube or perforating a preformed tube so that it becomes expandable. Many of these known stents require multiple steps to manufacture and require the use of materials that are difficult to form, increasing costs. It would be desirable to provide a stent that is simple and economical to manufacture, performs reliably and is simple to use. The present invention addresses those objectives.